Samba: troubleshooting smb taking 100% cpu but no samba activity

Title:

Troubleshooting smb taking 100% cpu but no samba activity

Author:

Douglas O’Leary <dkoleary@olearycomputers.com>

Description:

How to troubleshoot smbd taking 100% of cpu w/no samba activity

Date created:

07/2014

Date updated:

07/2014

Disclaimer:

Standard: Use the information that follows at your own risk. If you screw up a system, don’t blame it on me…

Problem;

Situation: System rebooted for non-related reasons. When it comes back, everything’s operational; but, smbd and winbind are taking 100% of a cpu each and smbstatus shows no activity.

What’s eating the cpu?

Solution:

Thanks to this url, I found the problem fairly quickly as a corrupted tdb file. Finding out which tdb file to remove, though, is the interesting bit.

1. find out where the tdb files are. Mine are under /var/lib/samba. /var/cache/samba might be another potential.

2. Run the following inline script:

   for f in *.tdb
   do
       echo ${f}
       tdbbackup -v ${f}
   done
   account_policy.tdb
   account_policy.tdb : 17 records
   brlock.tdb
   brlock.tdb : 0 records
   connections.tdb
   connections.tdb : 4 records
   gencache.tdb
   gencache.tdb : 93 records
   locking.tdb
   locking.tdb : 0 records
   messages.tdb
   messages.tdb : 0 records
   mutex.tdb
   mutex.tdb : 0 records
   netsamlogon_cache.tdb
   restoring netsamlogon_cache.tdb
   netsamlogon_cache.tdb.bak: No such file or directory
   notify.tdb
   notify.tdb : 0 records
   ntdrivers.tdb
   ntdrivers.tdb : 1 records
   ntforms.tdb
   ntforms.tdb : 0 records
   ntprinters.tdb
   ntprinters.tdb : 1 records
   registry.tdb
   registry.tdb : 90 records
   sessionid.tdb
   sessionid.tdb : 0 records
   share_info.tdb
   share_info.tdb : 1 records
   unexpected.tdb
   unexpected.tdb : 7 records
   winbindd_cache.tdb
   winbindd_cache.tdb : 70 records
   winbindd_idmap.tdb
   winbindd_idmap.tdb : 71 records
   

The tdbbackup command will hang on a corrupted tdb file. In my case, it was the gencache.tdb. Moved it out of the way and everything was good.

3. Remove the corrupted file and restart samba

Once done, smbd should go back to just sucking wind instead of sucking up all of your cpu cycles…